Heat activated tertiary amine urethane catalysts

ABSTRACT

This invention concerns a compound formed from a tertiary amine-carboxylic acid salt, where the carboxylic acid and tertiary amine are selected such that the catalyst salt is blocked at room temperature and becomes unblocked at an elevated temperature. The compound is useful as a heat activated urethane catalyst.

This application claims priority to U.S. provisional patent applicationSer. No. 60/466,990, filed May 1, 2003.

BACKGROUND OF INVENTION

This invention pertains to compounds useful as a heat activated urethanecatalyst that are formed from a tertiary amine-carboxylic acid salt,where the carboxylic acid and tertiary amine are selected such that thecompound unblocks at a given temperature.

Urethane is frequently polymerized through use of a catalyst such as atertiary amine. The inventors herein have recognized that a need existsfor a catalyst that is essentially inert at normal temperatures duringstorage, and which becomes active at an elevated temperature.

SUMMARY OF INVENTION

The present invention provides a solution to one or more of thedisadvantages and deficiencies described above.

In one broad respect, this invention is a heat activated urethanecatalyst which comprises a tertiary amine-carboxylic acid salt. Thissalt is blocked and inactive at room temperature, but becomes unblockedat an elevated temperature (it is heat activated). By unblocked it ismeant that the tertiary amine becomes a free, neutral compound and isnot present as a salt of the carboxylic acid. By elevated temperature itis meant, for example, a temperature above about 110° C., or above about125° C., or above about 135° C., or higher. In general, the salt becomesunblocked at a temperature above 135° C. In the acid salt, the tertiaryamine may be N,N-dimethylcyclohexylamine, pentamethyldiethlenetriamine,N,N-dimethyl-2(2-aminoethyoxy)ethanol, pentamehyldipropylenetriamine,tetramethyldipropylenetriamine, dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof; the tertiary amine may bedimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof; the carboxylic acidmay contain less than 30 carbons; the carboxylic acid may be oxalicacid, salicylic acid, or a combination thereof; the amine may beN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1; the mole ratio oftertiary amine to carboxylic acid may be less than 2:1; the mole ratioof tertiary amine to carboxylic acid may be less than about 1.5; themole ratio of tertiary amine to carboxylic acid may be from about 0.9:1to about 1.1; the acid salt may produce a carbonyl absorbance of at1730-1680 cm⁻¹ of at least 0.5 above 135° C.; or any combinationthereof.

In another broad respect, this invention is a process for themanufacture of a tertiary amine-carboxylic acid salt that becomesunblocked above about 110° C., or above about 125° C., or above about135° C., or higher, comprising: reacting a tertiary amine with acarboxylic acid to form the tertiary amine-carboxylic acid salts. Inthis process effective types and amounts of carboxylic acid and atertiary amine are reacted to form a tertiary amine:carboxylic acidsalt, wherein the carboxylic acid and tertiary amine are selected suchthat the salt for example unblocks at a temperature above about 110° C.,or above about 125° C., or above about 135° C., or higher. Thus thecarboxylic acid and tertiary amine are selected, and provided inamounts, such that the resulting salt unblocks at a temperature aboveabout 110° C., or above about 125° C., or above about 135° C., or agiven higher temperature. In this process, the tertiary amine may beN,N-dimethylcyclohexylamine, pentamethyldiethlenetriamine,N,N-dimethyl-2(2-aminoethyoxy)ethanol, pentamehyldipropylenetriamine,tetramethyldipropylenetriamine, dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof; the tertiary amine may bedimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof; the carboxylic acidmay contain less than 30 carbons; the carboxylic acid may be oxalicacid, salicylic acid, or a combination thereof; the amine may beN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1; the mole ratio oftertiary amine to carboxylic acid may be less than 2:1; the mole ratioof tertiary amine to carboxylic acid may be less than about 1.5; themole ratio of tertiary amine to carboxylic acid may be from about 0.9:1to about 1.1; the acid salt may produce a carbonyl absorbance of at1730-1680 cm⁻¹ of at least 0.5 above 135° C.; or any combinationthereof.

In another broad respect, this invention is a process for themanufacture of polyurethane, comprising: combining a diisocyanate, apolyol, and a catalyst, wherein the catalyst the catalyst is a tertiaryamine-carboxylic acid salt that becomes unblocked above 135° C., andheating the resulting composition to unblock the salt to therebypolymerize the composition to form a polyurethane composition.

The catalyst of this invention can be used in the manufacture of a pressmolded material, such as by applying (for example, by spraying)diisocyanate, polyol, and a catalyst on wood material, wherein thecatalyst is a tertiary amine-carboxylic acid salt that is blocked atroom temperature and becomes unblocked at an elevated temperature, andheating (for example while under pressure so as to form a press moldedmaterial) the resulting mixture to a temperature effective to unblockthe salt to produce unblocked tertiary amine.

The catalyst of this invention can be used for the production oforientated strand boards such as by applying a urethane composition onwood chips, applying such as by spraying a tertiary amine:carboxylicacid salt catalyst on the wood chips, compressing the chips, heating thecompressed chips so that at least a portion of the salt catalystunblocks to thereby initiate polymerization of the urethane composition.The urethane and salt may be sprayed separately or simultaneous inadmixture.

The catalyst of this invention can be used to make a composite formed ofwood chips and the polymerization product of a urethane composition andtertiary amine: carboxylic acid salt that unblocks at a temperature ofat least 135° C.

In the practice of this invention, the tertiary amine may beN,N-dimethylcyclohexylamine, pentamethyldiethlenetriamine,N,N-dimethyl-2(2-aminoethyoxy)ethanol, pentamehyldipropylenetriamine,tetramethyldipropylenetriamine, dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof; the tertiary amine may bedimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof; the carboxylic acidmay contain less than 30 carbons; the carboxylic acid may be oxalicacid, salicylic acid, or a combination thereof; the amine may beN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1; the mole ratio oftertiary amine to carboxylic acid may be less than 2:1; the mole ratioof tertiary amine to carboxylic acid may be less than about 1.5; themole ratio of tertiary amine to carboxylic acid may be from about 0.9:1to about 1.1; the acid salt may produce for example a carbonylabsorbance of at 1730-1680 cm⁻¹ of at least 0.5 above 135° C.; thediisocyanate may be an aliphatic, cycloaliphatic, aromatic, heterocyclicdiisocyanate, or combination thereof; the diisocyanate may benaphthalene bis (4-phenyl isocyanate), 4,4′-diphenylmethanediisocyanate, 1,3- and 1,4-phenylene diisocyanate, toluene 2,4- and2,6-diisocyanate, diphenylmethane 2,4′- or 4,4′-diisocyanate, mixturesthereof or oligomers thereof or mixtures of oligomers the polyol mayhave two to eight hydroxyl groups; the diisocyanate and polyol may beemployed so as to provide a NCO/OH ratio of from 1.1:1 to 10:1; or anycombination thereof.

This invention has a number of advantages. For example, the tertiaryamine-carboxylic acid salt of this invention is blocked and stable atroom temperature and becomes unblocked. Advantageously, the unblockingoccurs generally at a temperature above about 110° C., or above about125° C., or above about 135° C., or at higher given temperatures.

In general, unblocking can be observed using Fourier transform infrared(FTIR) spectroscopy. Unblocking is generally indicated by a carbonylabsorbance at 1730-1680 cm⁻¹ of at least 0.5 above 135° C., and inanother embodiment at least 0.5 above 150° C. The catalyst becomesactive when it is unblocked, whereby polymerization of the urethaneprecursors commences.

Surprisingly, the catalyst of this invention shows little or no activityat room temperature but becomes active at elevated temperature. Theactivation temperature can be controlled by choice of the amine andcarboxylic acid. An additional surprising result is the 1:1 mole ratioof N,N-dimethyl-2-(2-aminoethoxy)ethanol:oxalic acid gave this propertywhile the 2:1 mole ratio of these components did not.N,N-dimethyl-2-(2-aminoethoxy)ethanol is available commercially underthe name JEFFCAT ZR-70. In one embodiment, the mole ratio of tertiaryamine to carboxylic acid is less than 2:1, in another embodiment is lessthan about 1.5, and in another embodiment is less than about 1.1. In oneembodiment, the mole ratio of tertiary amine to carboxylic acid is fromabout 0.9:1 to about 1.1, and in another embodiment is about 1:1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the difference in isocyanate absorbances between acatalyzed, unblocked system and a non-catalyzed system as per example 2.

FIG. 2 shows the difference in carbonyl absorbances between a catalyzed,unblocked system and a non-catalyzed system as per example 2.

FIG. 3 shows the differences in isocyanate absorbances for catalysts A,C, F, G, no catalyst, and JEFFCAT™ ZR-70 as per example 2.

FIG. 4 shows the difference in carbonyl absorbances for catalysts A, C,F, G, no catalyst, and JEFFCAT™ ZR-70 as per example 2.

FIG. 5 shows the isocyanate absorbances for catalysts A, D, H, J, S, nocatalyst, and JEFFCAT™ ZR-70 as described in the examples.

FIG. 6 shows the carbonyl absorbances for catalysts A, D, H, J, S, nocatalyst, and JEFFCAT™ ZR-70 as described in the examples.

FIG. 7 shows the difference in isocyanate absorbances for catalystsprepared from 1:1 mole ratio versus a mole ratio of 2:1 of tertiaryamine to carboxylic acid.

FIG. 8 shows the difference in carbonyl absorbances for catalystsprepared from 1:1 mole ratio versus a mole ratio of 2:1 of tertiaryamine to carboxylic acid.

FIGS. 9 and 11 show the isocyanate absorbances for certain catalystswhich did not unblock.

FIGS. 10 and 12 show the carbonyl absorbances for certain catalystswhich did not unblock.

DETAILED DESCRIPTION OF THE INVENTION

The tertiary amine—carboxylic acid salts of this invention can beprepared from a variety of starting compounds. The salts are made bycontacting a tertiary amine with a carboxylic acid, typically in anaqueous mixture. The salts may be isolated and purified using standardtechniques well known to one of skill in the art. The salts are used asheat activated catalysts for urethanes.

In general, the application of this technology in polyurethane involvesheating a mixture of an isocyanate and some form of a hydroxyl typematerial in the presence of the blocked tertiary amine-carboxylic acidsalt to a temperature such that the salt becomes unblocked, with thecatalyst thereby becoming activated. The temperature at which thecatalyst becomes unblocked may vary depending on the specific amine/acidsalt at issue.

The tertiary amines used in the practice of this invention are selectedsuch that the tertiary amine selected in combination with a givencarboxylic acid is blocked at room temperature and becomes unblocked atelevated temperature, such as above about 110° C. and in one embodimentabove about 125° C., and in another embodiment above about 135° C. Inone embodiment, the catalyst may provide a carbonyl absorbance at1730-1680 cm⁻¹ of at least 0.5 above 135° C. as measured in admixturewith polyurethane precursors such as described. These tertiary aminesmay be referred to as effective tertiary amines, in the context of thisinvention. Tertiary amines can be readily determined as to whether incombination with a given carboxylic acid the tertiary amine is aneffective tertiary amine through routine experimentation, as by formingthe salt, combining the salt with polyurethane precursors, exposing theresulting composition to heat and determining whether the catalyst saltbecomes unblocked above a given temperature such as above about 135° C.As such, certain tertiary amines may work with a given carboxylic acidbut not with other carboxylic acids. In general, the effective tertiaryamines contain less than 30 carbon atoms, and are aliphatic amines whichmay optionally include additional functionality such as one or moreether and/or one or more alcohol groups. Representative examples of suchtertiary amines include but are not limited toN,N-dimethylcyclohexylamine (which can be referred to as “DMCHA”),pentamethyldiethlenetriamine (which can be referred to as “PMDETA”),N,N-dimethyl-2(2-aminoethyoxy)ethanol (which can be referred to as“DMDGA”), pentamehyldipropylenetriamine (currently availablecommercially from Huntsman under the trade name ZR-40),tetramethyldipropylenetriamine (currently available commercially fromHuntsman under the trade name ZR-50B), dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, andcombinations thereof. In one embodiment, the tertiary amine isdimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof

The carboxylic acids used in the practice of this invention are selectedsuch that the carboxylic acid selected in combination with a giventertiary amine is blocked at room temperature and becomes unblocked atelevated temperature, such as above about 110° C., or above about 125°C., or above about 135° C., or higher, and may provide for example acarbonyl absorbance at 1730-1680 cm⁻¹ of at least 0.5 above 135° C.These carboxylic acids may be referred to as effective carboxylic acids,in the context of this invention. As such, certain carboxylic acids maywork with a given tertiary amine but not with other tertiary amines.Carboxylic acids can be readily determined as to whether in combinationwith a given tertiary amine the carboxylic acid is an effectivecarboxylic acid through routine experimentation, as by forming the salt,combining the salt with polyurethane precursors, exposing the resultingcomposition to heat and determining whether the catalyst salt becomesunblocked above about 110° C., or above about 125° C., or above about135° C., or higher. In general, the effective carboxylic acids containless than 30 carbons, and may optionally include additionalfunctionality such as one or more ether and/or one or more alcoholgroups. Representative examples of such carboxylic acids include but arenot limited to oxalic acid, salicylic acid, and combinations thereof.

Polyurethane is a well known polymer which, in general, is made byreacting diisocyanate, polyol, and the catalyst. A number of differentkinds of polyurethanes can be produced depending on the nature of thepolyol used and degree of cross-linking achieved, for example. If thepolyurethane is a foam, a suitable blowing agent should be included,such as water as is known in the art. Polyurethane foams generally havea higher amount of cross-linking. Aliphatic, cycloaliphatic, aromatic,and heterocyclic diisocyanates can be used as starting materials, whichin general may contain up to about 20 carbon atoms. Representativeexamples of such diisocyanates include but are not limited tonaphthalene bis (4-phenyl isocyanate), 4,4′-diphenylmethanediisocyanate, 1,3- and 1,4-phenylene diisocyanate, toluene 2,4- and2,6-diisocyanate (TDI), diphenylmethane 2,4′- or 4,4′-diisocyanate(MDI), and mixtures and/or oligomers (prepolymers) thereof. If aprepolymer is employed, its molecular weight is typically about 300 to2000. Such a prepolymer is typically made by reacting a polyol with anexcess amount of diisocyanate.

The polyol can be any conventional or specialty polyol used in thepolyurethane field. Typically, the polyol has two to eight hydroxylgroups. In one embodiment, the polyol has a molecular weight of from 400to 10,000, in some instances from 600 to 5,000. The polyols can includepolyesters, polyethers, polythioethers, polyacetals, polycarbonates, andpolyester amides containing two to eight hydroxyl groups, and in someinstances two to four hydroxyl groups.

In general, the diisocyanate and polyol are employed so as to provide aNCO/OH ratio of from 1.1:1 to 10:1, typically 1.5:1 to 5:1.

For polyurethane formed from the heat activated salt catalyst of thisinvention, the polyurethane is made by first combining the polyurethaneprecursors (diisocyanate, polyol, catalyst, and any other additives suchas a blowing agent if foam is desired). Advantageously, the saltcatalyst of this invention does not initiate polyurethane formation atroom temperature. Next, the precursor composition is heated to unblockthe salt, whereby the unblocked tertiary amine catalyst initiatespolyurethane formation.

The polyurethane compositions according to the invention may be appliedas one or more layers to substrates by known methods such as spraying,brush coating, immersion or flooding or by means of rollers or doctorapplicators. A substrate to be coated may be treated with suitableprimers before the process according to the invention is carried out.The process according to the invention is suitable for the formation ofcoatings on any substrates, e.g., metals, plastics, wood or glass. Thepolyurethane compositions may also be used to form articles per se.

The amine/carboxylic acid salt of this invention can be used as acatalyst for polyurethane in the production of structural product basedon wood materials. A representative example of such a structural productis an orientated strand board (OSB), which may be described as anengineered, mat-formed panel product made of strands, flakes, or waferssliced from wood logs that is bonded with a polyurethane binder underheat and pressure. The wood materials that can be employed in thepractice of this invention may vary widely. Representative examples ofsuch wood materials include but are not limited to wood, bark, cork,bagasse, straw, flax, bamboo, alfa grass, rice husks, sisal, and coconutfibers. The material may be present in the form of granules, chips,fibers, or flour. The materials may have an intrinsic water content of 0to 35 percent by weight, frequently from 5 to 25 percent by weight. Thewood material is typically mixed with the polyurethane precursors (i.e.,the diisocyanate, polyol, and catalyst) so as to provide a finalcomposition that contains from about 1 to about 50, more typically 1 to15 percent by weight, of the polyurethane precursors. Typically, thewood material is sprayed with these materials to effect mixing, as isknown to one of skill in the art. An advantage of this invention is thatthe catalyst has essentially no catalytic effect until heat activatedabove an elevated temperature such as above about 110° C., above about125° C., or above about 135° C. The polyurethane so formed serves as abinder for the wood material to hold the compress molded producttogether.

When sprayed, the catalyst may be sprayed in admixture with water or oneor more organic solvents. For example, ethylene carbonate, propylenecarbonate, or mixtures thereof can be employed as a solvent so thatapplication of the catalyst. In general, an organic solvent should notreact with the diisocyanate or polyol, evaporate readily, and becompliant with environmental regulations for a given end use. Additionalrepresentative classes of organic solvents that can be employed includebut are not limited to aprotic organic solvents capable of solubilizingthe components, such as esters including ethyl acetate, propyl acetate,and butyl acetate, ethers, hydrocarbons, ketones, amides, and so on.Additional examples of suitable solvents include xylene, methyl isobutylketone, methoxypropyl acetate, N-methyl pyrrolidone, Solvesso solvent,petroleum hydrocarbons, iso-butanol, butyl glycol, chlorobenzenes andmixtures of such solvents.

The mixture of wood product and polymeric precursors are then typicallycompacted in a mold. Next the compacted mixture is exposed to rapidheating so that at least a portion of the compacted mixture achieves atemperature above about 135° C., for example, often under pressure up to3 atmospheres, though atmospheric and reduced pressure may also be used.The temperature of the heat applied to the compacted material to betreated is typically up to 180° C. to 200° C., though higher and lowertemperatures can be used. Typically a temperature gradient develops overthe molded product, with temperatures above 135° C. in at least aportion of the product, thereby initiating unblocking of the salt andthus initiating curing of the polyurethane.

Other materials useful in the reaction may include surfactants, polyols,water, wood products, plastasizers, mold release agents, and flameretardants, as well as other common polyurethane additives.

For example, an ultraviolet stabilizer can be employed in the practiceof this invention. Such ultraviolet stabilizers may include a stericallyhindered piperidine derivative, such as an alkyl substituted hydroxypiperidine derivative. In one embodiment, the ultraviolet stabilizerincludes the reaction product of an ester of a carboxylic acid and toalkyl substituted hydroxy piperidines. In one embodiment, theultraviolet stabilizer is bis-(1, 2, 2, 6, 6-tetramethyl-4-piperidinyl)sebacate, known as TINUVIN™ 765 and commercially available fromCiba-Geigy.

An UV absorber can be used in the instant invention, and may generallyinclude a substituted benzotriazole, such as a phenyl substitutedbenzotriazole. In one embodiment, the UV stabilizer is a hydroxyl, alkylsubstituted benzotriazole. In another embodiment, the UV stabilizer is2-(2′-hydroxy-3′,5′-di-tert-amylphenyl)benzotriazole, known as TINUVIN™and commercially available from Ciba-Geigy.

An antioxidant may be used in the instant invention such as asubstituted, sterically hindered phenol, such as a substituted ester ofhydroxyhydrocinnamic acid. In one embodiment, the antioxidant element isa 3,5-dialkyl ester of hydroxyhydrocinnamic acid, and another embodimentis octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, known asIRGANOX™ 1076 and commercially available from Ciba-Geigy.

The amount of additive incorporated in the polyurethane depends onseveral factors, including the desired stability of the polyurethane, sothe amount of additive can be adjusted according to the intended use ofthe polyurethane. Generally, a useful amount of additive in thepolyurethane can be an amount of up to about 5 percent by weight, and inone embodiment is in an amount of from about 0.5 to about 3 percent byweight.

The following examples are illustrative of this invention and are notintended to limit the scope of the invention or claims hereto. Unlessotherwise denoted all percentages are by weight. Example 1 describes thesynthesis of various acid blocked amine catalysts. Example 2 illustratesthe effectiveness of these derivatives over the control material. Thecontrol material, catalyst G, is the material described in U.S. Pat. No.6,007,649.

EXAMPLE 1 Preparation of Catalysts

The general procedures for these three examples are as follows. To areactor containing a stirrer bar, carboxylic acid and water (which isoptional in the practice of this invention) were added then stirred for10 minutes. The tertiary amine was then added slowly over athirty-minute period with stirring. The mixture was then stirred for anadditional 10 minutes. Mole ratio Water, Catalyst Acid Amine amine/acidwt % A Oxalic JEFFCAT ZR-70 1.0 20 B (comparison) Oxalic JEFFCAT ZR-702.0 20 C Oxalic JEFFCAT DMEA 1.0 20 D Oxalic JEFFCAT Z-110 1.0 20 F(comparison) Malonic JEFFCAT ZR-70 2.0 20 G (comparison) Malonic JEFFCATDMEA 1.0 20 H Salicylic JEFFCAT ZR-70 1.0 0 I Salicylic JEFFCAT DMEA 1.020 J Salicylic JEFFCAT Z-110 1.0 20 K (comparison) Adipic JEFFCAT ZR-701.0 20 L (comparison) Adipic JEFFCAT Z-110 1.0 20 M (comparison)Succinic JEFFCAT ZR-70 0.63 20 N (comparison) Maleic JEFFCAT ZR-70 1.027 O (comparison) Oxalic JEFFCAT DPA 1.0 20 P (comparison) LacticJEFFCAT ZR-70 1.0 7 Q (comparison) Oxalic JEFFCAT ZF-20 1.0 20 R(comparison) Formic JEFFCAT ZR-70 1.0 1JEFFCAT ZR-70: dimethylaminoethoxyethanol (which may also be referred toas N,N-dimethyl-2-(2-aminoethoxy)ethanol)JEFFCAT Z-110: N,N,N′-trimethylaminoethyl-ethanolamineJEFFCAT DMEA: ethanol, 2-(dimethylamino)- (which may also be referred toas dimethylethanolamine)JEFFCAT ZF-20: 2,2′-oxybis(N,N-dimethylethanamine)JEFFCAT DPA: 2-propanol, 1,1′-((3-(dimethylamino)propyl)imino)bis

-   -   JEFFCAT ZR-70: dimethylaminoethoxyethanol (which may also be        referred to as N,N-dimethyl-2-(2-aminoethoxy)ethanol)    -   JEFFCAT Z-110: N,N,N′-trimethylaminoethyl-ethanolamine    -   JEFFCAT DMEA: ethanol, 2-(dimethylamino)-(which may also be        referred to as dimethylethanolamine)    -   JEFFCAT ZF-20: 2,2′-oxybis(N,N-dimethylethanamine)    -   JEFFCAT DPA: 2-propanol,        1,1′-((3-(dimethylamino)propyl)imino)bis

EXAMPLE 2 FTIR Analysis of the Reaction of the Catalyst and anIsocyanate Component

The effect that these catalysts have on a PIR foam was determined byusing a REACTFTIR 1000 instrument using a heated probe. The heated probewas programmed to start at 70 C and hold at this temperature for 10minutes. It was ramped up to 180 C over a thirty-minute period. At thispoint, it was held for 15 minutes at 180 C. Approximately 574 FTIRspectra were recorded during this time period from 800-4000 cm⁻¹. Theformulation used to test these catalyst consisted of a pre-blend ofRUBINATE 1840 (70 pbw), diisononylphthalate (20 pbw), and TegostabB-8407, (7.0 pbw). Prior to placing several drops unto the FTIR probe,0.6 pbw of water and an appropriate amount of acid blocked catalyst,1.73 mmole, was mixed into the pre-blend. The amounts used are shown inthe following Table. Catalyst 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 A0.46 B 0.37 C 0.39 D 0.49 F 0.51 G 0.42 H 0.47 J 0.62 K 0.60 L 0.64 M0.52 N 0.52 P 0.41 Q 0.51 R 031 S 0.23 (JEFFCAT ZR-70)

The FIGS. show the effect that the catalysts have on either theisocyanate or carbonyl absorbance. Isocyanate absorbance will decreaseover time as the isocyanate is consumed. Carbonyl absorbance willincrease as the amount of carbonyl absorbing species increases in thereacting mixture. The graph of the temperature profile is also shown inall of these graphs. The right side of each graph shows the temperaturescale. Inspection of some of the these graphs will show that, at acertain temperature, either a sharp decrease in isocyanate absorbance,which translates to using up the isocyanate quicker, or a sharp rise incarbonyl absorbance, which translates to forming more carbonyl species.These carbonyl species are either from the reaction of the isocyanateand water, isocyanate and polyol, or trimerization of the isocyanateinto an isocyanurate material or any combination of these reactions.

FIGS. 1 and 2 shows the difference in isocyanate and carbonyl absorbancebetween a catalyzed (JEFFCAT ZR-70) or unblocked system and anon-catalyzed system. The catalyzed system reacts quicker than theuncatalyzed system. The catalyzed system is not blocked in any manner.For an ideal blocked catalyst, the isocyanate absorbance should closelyfollow the uncatalyzed system but should accelerate at some point andstart consuming isocyanate.

The following figures illustrate the improvement over the art, whichuses JEFFCAT DMEA and malonic acid (catalyst G). A delay is shown forthis derivative but it never kicks in to accelerate the consumption ofthe isocyanate, FIG. 3. It does slowly use up the isocyanate at agreater rate than the uncatalyzed system. It functions as a blockedcatalyst but does not unblock at any particular temperature. There is apoint where formation of the carbonyl species slowly increases, as shownin FIG. 4.

An improvement is shown in FIGS. 3 and 4 by the delay of JEFFCAT DMEAand oxalic acid (catalyst C) and in particular at about 170° C. wherethis derivative starts to accelerate the consumption of the isocyanateand the formation of carbonyl species. The higher carbonyl absorbance ofthe JEFFCAT DMEA and oxalic acid shows that a higher concentration ofthe carbonyl species is formed from this catalyst.

A further improvement of this invention is illustrated by the catalystcomposed of JEFFCAT ZR-70 and oxalic acid (catalyst A). Again, as withJEFFCAT DMEA and oxalic acid, there is a point at about 150° C. in theisocyanate absorbance where JEFFCAT ZR-70 and oxalic acid acceleratesthe consumption of the isocyanate. This trend is also seen in thecarbonyl absorbance. Surprisingly, the temperature of the conversion ofthe isocyanate and formation of carbonyl species occurs at a lowertemperature for JEFFCAT ZR-70 than JEFFCAT DMEA, that is, 150° C. versus170° C.

The uniqueness of the salt of JEFFCAT ZR-70 and oxalic acid is furtherillustrated by observing the isocyanate and carbonyl absorbenciesprofiles of JEFFCAT ZR-70 and malonic acid (catalyst F) and compare itwith the unblocked JEFFCAT ZR-70. They are practically identical. Thereis no delay for catalyst F like there is with catalyst A.

Another surprising aspect of this invention is that JEFFCAT Z-110 alsoshows the unusual effect of blocking and then unblocking when a certaintemperature is reached. This is shown in FIGS. 5 and 6. The temperatureat which the JEFFCAT Z-110+oxalic acid (catalyst D) becomes unblockedand starts to consume isocyanate at a faster rate is lower than the saltof JEFFCAT ZR-70 and oxalic acid (catalyst A).

Another acid that was found to work with these amine catalysts to blockand then unblock at elevated temperatures is salicylic acid. Salts ofJEFFCAT ZR-70 (catalyst H) and JEFFCAT Z-110 (catalyst J) are also shownin these figures. Close inspection of the first 500 seconds with thesalicylic acid derivative shows a quick isocyanate consumption followedby a somewhat flat consumption of the isocyanate up until the catalystbecomes active or unblocks similar trend is seen in the isocyanurateabsorbance.

The reaction of JEFFCAT ZR-70/oxalic acid was done in a 1/1 mole ratio(catalyst A) and a 2/1 mole ratio (catalyst B). The 2/1 mole ratio wasnot as effective at blocking or delaying the isocyanate consumption orisocyanurate formation as the 1/1 salt, as seen FIGS. 7 and 8. The 2/1mole ratio salt did not show any acceleration in isocyanate consumptionas opposed to the 1/1 mole ratio salt, which did.

Other catalysts which did not show any signs of blocking and unblocking,and thus are comparative examples, are shown in FIGS. 9-12. Theseexamples further demonstrate the uniqueness of the catalysts of thisinvention.

Further modifications and alternative embodiments of this invention willbe apparent to those skilled in the art in view of this description.Accordingly, this description is to be construed as illustrative onlyand is for the purpose of teaching those skilled in the art the mannerof carrying out the invention. It is to be understood that the forms ofthe invention herein shown and described are to be taken as illustrativeembodiments. Equivalent elements or materials may be substituted forthose illustrated and described herein, and certain features of theinvention may be utilized independently of the use of other features,all as would be apparent to one skilled in the art after having thebenefit of this description of the invention.

1. A tertiary amine-carboxylic acid salt that is blocked at roomtemperature and becomes unblocked at an elevated temperature.
 2. Theacid salt of claim 1 wherein the tertiary amine isN,N-dimethylcyclohexylamine, pentamethyldiethlenetriamine,N,N-dimethyl-2(2-aminoethyoxy)ethanol, pentamehyldipropylenetriamine,tetramethyldipropylenetriamine, dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof.
 3. The acid salt of claim 1 wherein the tertiaryamine is dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof
 4. The acid salt of claim 1 wherein the carboxylicacid contains less than 30 carbons.
 5. The acid salt of claim 1 whereinthe carboxylic acid is oxalic acid, salicylic acid, or a combinationthereof.
 6. The acid salt of claim 1 wherein the tertiary amine isN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1.
 7. The acid salt ofclaim 1 wherein the mole ratio of tertiary amine to carboxylic acid isless than 2:1.
 8. The acid salt of claim 1 wherein the mole ratio oftertiary amine to carboxylic acid is less than about 1.5.
 9. The acidsalt of claim 1 wherein the mole ratio of tertiary amine to carboxylicacid from about 0.9:1 to about 1.1.
 10. The acid salt of claim 1 whereinthe acid salt produces a carbonyl absorbance of at 1730-1680 cm⁻¹ of atleast 0.5 above 135° C.
 11. A process for the manufacture of a tertiaryamine-carboxylic acid salt that is blocked at room temperature andbecomes unblocked at an elevated temperature, comprising: reacting atertiary amine with a carboxylic acid to form the tertiaryamine-carboxylic acid salts.
 12. The process of claim 11 wherein thetertiary amine is N,N-dimethylcyclohexylamine,pentamethyldiethlenetriamine, N,N-dimethyl-2(2-aminoethyoxy)ethanol,pentamehyldipropylenetriamine, tetramethyldipropylenetriamine,dimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof.
 13. The process ofclaim 11 wherein the tertiary amine is dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof
 14. The process of claim 11 wherein the carboxylicacid contains less than 30 carbons.
 15. The process of claim 11 whereinthe carboxylic acid is oxalic acid, salicylic acid, or a combinationthereof.
 16. The process of claim 11 wherein the tertiary amine isN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1.
 17. The process ofclaim 11 wherein the mole ratio of tertiary amine to carboxylic acid isless than 2:1.
 18. The process of claim 11 wherein the mole ratio oftertiary amine to carboxylic acid is less than about 1.5.
 19. Theprocess of claim 11 wherein the mole ratio of tertiary amine tocarboxylic acid from about 0.9:1 to about 1.1.
 20. The process of claim11 wherein the acid salt produces a carbonyl absorbance of at 1730-1680cm⁻¹ of at least 0.5 above 135° C.
 21. A process for the manufacture ofpolyurethane, comprising: combining a diisocyanate, a polyol, and acatalyst, wherein the catalyst the catalyst is a tertiaryamine-carboxylic acid salt that is blocked at room temperature andbecomes unblocked at an elevated temperature, and heating the resultingcomposition to unblock the salt to thereby polymerize the composition toform a polyurethane composition.
 22. The process of claim 21 wherein thetertiary amine is N,N-dimethylcyclohexylamine,pentamethyldiethlenetriamine, N,N-dimethyl-2(2-aminoethyoxy)ethanol,pentamehyldipropylenetriamine, tetramethyldipropylenetriamine,dimethylaminoethoxyethanol, N,N,N′-trimethylaminoethyl-ethanolamine,2-(dimethylamino)-ethanol, or a combination thereof.
 23. The process ofclaim 21 wherein the tertiary amine is dimethylaminoethoxyethanol,N,N,N′-trimethylaminoethyl-ethanolamine, 2-(dimethylamino)-ethanol, or acombination thereof.
 24. The process of claim 21 wherein the carboxylicacid contains less than 30 carbons.
 25. The process of claim 21 whereinthe carboxylic acid is oxalic acid, salicylic acid, or a combinationthereof.
 26. The process of claim 21 wherein the tertiary amine isN,N-dimethyl-2-(2-aminoethoxy)ethanol, the carboxylic acid is oxalicacid, and are present in a mole ratio of about 1:1.
 27. The process ofclaim 21 wherein the mole ratio of tertiary amine to carboxylic acid isless than 2:1.
 28. The process of claim 21 wherein the mole ratio oftertiary amine to carboxylic acid is less than about 1.5.
 29. Theprocess of claim 21 wherein the mole ratio of tertiary amine tocarboxylic acid from about 0.9:1 to about 1.1.
 30. The process of claim21 wherein the acid salt produces a carbonyl absorbance of at 1730-1680cm⁻¹ of at least 0.5 above 135° C.
 31. The process of claim 21 whereinthe diisocyanate is an aliphatic, cycloaliphatic, aromatic, heterocyclicdiisocyanate, or combination thereof.
 32. The process of claim 21wherein the diisocyanate is naphthalene bis (4-phenyl isocyanate),4,4′-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate,toluene 2,4- and 2,6-diisocyanate, diphenylmethane 2,4′- or4,4′-diisocyanate, mixtures thereof or oligomers thereof or mixtures ofoligomers.
 33. The process of claim 21 wherein the polyol has two toeight hydroxyl groups.
 34. The process of claim 21 wherein thediisocyanate and polyol are employed so as to provide a NCO/OH ratio offrom 1.1:1 to 10:1.